The present invention relates to a method of suspension polymerization of vinyl chloride.
It has been known to polymerize vinyl chloride by a suspension polymerization by dispersing vinyl chloride in an aqueous medium in the presence of an oil soluble catalyst for polymerization.
It has been also known to use a suspending agent for dispersing vinyl chloride monomer in an aqueous medium as suitable size of particles in the suspension polymerization.
However, in the conventional suspension polymerization using one or more conventional suspending agents, it has been hard to obtain resins having desired powdery characteristics such as bulk density, particle distribution, plasticizer absorption velocity and gelation velocity and quality characteristics such as fish-eye, heat stability, etc.
In order to overcome the difficulties, a method of adding a suspending agent during the polymerization has been proposed as Japanese Unexamined Patent Publication No. 82190/1975 and a method of combining a surfactant and a polyvalent metal salt has been proposed as Japanese Patent Publication No. 6347/1975. However, these methods are not sufficient to overcome the difficulties.